/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 *
 * Add shutDown method to fix Angel client exit problem.
 */

/**
 * Add shutDown method to fix Angel client exit problem.
 */
package com.tencent.angel.ipc;

import com.tencent.angel.exception.RetriesExhaustedException;
import com.tencent.angel.utils.NetUtils;
import com.tencent.angel.utils.ReflectionUtils;
import java.io.IOException;
import java.lang.reflect.Field;
import java.lang.reflect.Proxy;
import java.net.ConnectException;
import java.net.InetSocketAddress;
import java.net.SocketTimeoutException;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import javax.net.SocketFactory;
import org.apache.hadoop.conf.Configuration;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

@SuppressWarnings("rawtypes")
// TODO: 17/6/27 by zmyer
public class MLRPC {

    protected static final Logger LOG = LoggerFactory.getLogger(MLRPC.class);

    /**
     * Configuration key for the {@link RpcEngine} implementation to load to handle connection
     * protocols. Handlers for individual protocols can be configured using
     * {@code "ml.rpc.engine." + protocol.class.name}.
     */
    public static final String RPC_ENGINE_PROP = "ml.rpc.engine";

    // track what RpcEngine is used by a proxy class, for stopProxy()
    private static final Map<Class, RpcEngine> PROXY_ENGINES = new HashMap<>();

    // cache of RpcEngines by protocol
    private static final Map<Class, RpcEngine> PROTOCOL_ENGINES = new HashMap<>();

    /** Construct a server for a protocol implementation instance. */
    @SuppressWarnings("unchecked")
    public static RpcServer getServer(Class protocol, final Object instance,
        final Class<?>[] ifaces, String bindAddress, int port, Configuration conf)
        throws IOException {
        return getProtocolEngine(protocol, conf).getServer(protocol, instance, ifaces, bindAddress,
            port, conf);
    }

    // return the RpcEngine configured to handle a protocol
    private static synchronized RpcEngine getProtocolEngine(Class protocol, Configuration conf) {
        RpcEngine engine = PROTOCOL_ENGINES.get(protocol);
        if (engine == null) {
            Class<?> defaultEngine = ProtobufRpcEngine.class;
            LOG.debug("Using " + defaultEngine.getName() + " for " + protocol.getName());
            engine = (RpcEngine) ReflectionUtils.newInstance(defaultEngine, conf);
            if (protocol.isInterface())
                PROXY_ENGINES.put(Proxy.getProxyClass(protocol.getClassLoader(), protocol), engine);
            PROTOCOL_ENGINES.put(protocol, engine);
        }
        return engine;
    }

    /**
     * Construct a client-side proxy object that implements the named protocol, talking to a server at
     * the named address.
     *
     * @param protocol interface
     * @param clientVersion version we are expecting
     * @param addr remote address
     * @param conf configuration
     * @param factory socket factory
     * @param rpcTimeout timeout for each RPC
     * @return proxy
     * @throws java.io.IOException e
     */
    private static VersionedProtocol getProxy(Class<? extends VersionedProtocol> protocol,
        long clientVersion, InetSocketAddress addr, Configuration conf, SocketFactory factory,
        int rpcTimeout, List<String> addrList4Failover) throws IOException {
        RpcEngine engine = getProtocolEngine(protocol, conf);
        return engine.getProxy(protocol, clientVersion, addr, conf, factory, rpcTimeout,
            addrList4Failover);
    }

    /**
     * Construct a client-side proxy object with the default SocketFactory
     *
     * @param protocol interface
     * @param clientVersion version we are expecting
     * @param addr remote address
     * @param conf configuration
     * @param rpcTimeout timeout for each RPC
     * @return a proxy instance
     * @throws java.io.IOException e
     */
    private static VersionedProtocol getProxy(Class<? extends VersionedProtocol> protocol,
        long clientVersion, InetSocketAddress addr, Configuration conf, int rpcTimeout,
        List<String> addrList4Failover) throws IOException {

        return getProxy(protocol, clientVersion, addr, conf, NetUtils.getDefaultSocketFactory(conf),
            rpcTimeout, addrList4Failover);
    }

    static long getProtocolVersion(Class<? extends VersionedProtocol> protocol)
        throws NoSuchFieldException, IllegalAccessException {
        Field versionField = protocol.getField("VERSION");
        versionField.setAccessible(true);
        return versionField.getLong(protocol);
    }

    /**
     * @param protocol protocol interface
     * @param clientVersion which client version we expect
     * @param addr address of remote service
     * @param conf configuration
     * @param maxAttempts max attempts
     * @param rpcTimeout timeout for each RPC
     * @param timeout timeout in milliseconds
     * @return proxy
     * @throws java.io.IOException e
     */
    @SuppressWarnings("unchecked")
    static VersionedProtocol waitForProxy(Class protocol, long clientVersion,
        InetSocketAddress addr, Configuration conf, int maxAttempts, int rpcTimeout,
        long timeout, List<String> addrList4Failover) throws IOException {
        long startTime = System.currentTimeMillis();
        IOException ioe;
        int reconnectAttempts = 0;
        while (true) {
            try {
                return getProxy(protocol, clientVersion, addr, conf, rpcTimeout, addrList4Failover);
            } catch (SocketTimeoutException te) { // namenode is busy
                LOG.info("Problem connecting to server: " + addr, te);
                ioe = te;
            } catch (IOException ioex) {
                // We only handle the ConnectException.
                LOG.info("Get proxy failed!", ioex);
                ConnectException ce = null;
                if (ioex instanceof ConnectException) {
                    ce = (ConnectException) ioex;
                    ioe = ce;
                } else if (ioex.getCause() != null && ioex.getCause() instanceof ConnectException) {
                    ce = (ConnectException) ioex.getCause();
                    ioe = ce;
                } else if (ioex.getMessage().toLowerCase().contains("connection refused")) {
                    ce = new ConnectException(ioex.getMessage());
                    ioe = ce;
                } else {
                    // This is the exception we can't handle.
                    ioe = ioex;
                }
                if (ce != null) {
                    handleConnectionException(++reconnectAttempts, maxAttempts, protocol, addr, ce);
                }
            }
            // check if timed out
            if (System.currentTimeMillis() - timeout >= startTime) {
                throw ioe;
            }

            // wait for retry
            try {
                Thread.sleep(1000);
            } catch (InterruptedException ie) {
                // IGNORE
            }
        }
    }

    /**
     * @param retries current retried times.
     * @param maxAttmpts max attempts
     * @param protocol protocol interface
     * @param addr address of remote service
     * @param ce ConnectException
     * @throws RetriesExhaustedException retry exhaust exception that throw
     */
    private static void handleConnectionException(int retries, int maxAttmpts, Class<?> protocol,
        InetSocketAddress addr, ConnectException ce) throws RetriesExhaustedException {
        if (maxAttmpts >= 0 && retries >= maxAttmpts) {
            LOG.info("Server at " + addr + " could not be reached after " + maxAttmpts
                + " tries, giving up.");
            throw new RetriesExhaustedException("Failed setting up proxy " + protocol + " to "
                + addr.toString() + " after attempts=" + maxAttmpts, ce);
        }
    }

    static void stopProxy(VersionedProtocol proxy) {
        if (proxy != null) {
            LOG.debug("stop proxy");
            getProxyEngine(proxy).stopProxy(proxy);
        }
    }

    // return the RpcEngine that handles a proxy object
    private static synchronized RpcEngine getProxyEngine(Object proxy) {
        return PROXY_ENGINES.get(proxy.getClass());
    }

    /**
     * Close all connections and all workers.
     */
    static synchronized void shutDown() {
        Iterator<Map.Entry<Class, RpcEngine>> iter = PROXY_ENGINES.entrySet().iterator();
        while (iter.hasNext()) {
            iter.next().getValue().shutDown();
            iter.remove();
        }
    }
}
